1/* Dwarf2 Expression Evaluator
2   Copyright 2001, 2002, 2003 Free Software Foundation, Inc.
3   Contributed by Daniel Berlin (dan@dberlin.org)
4   This file is part of GDB.
5
6   This program is free software; you can redistribute it and/or modify
7   it under the terms of the GNU General Public License as published by
8   the Free Software Foundation; either version 2 of the License, or
9   (at your option) any later version.
10
11   This program is distributed in the hope that it will be useful,
12   but WITHOUT ANY WARRANTY; without even the implied warranty of
13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14   GNU General Public License for more details.
15
16   You should have received a copy of the GNU General Public License
17   along with this program; if not, write to the Free Software
18   Foundation, Inc., 59 Temple Place - Suite 330,
19   Boston, MA 02111-1307, USA.  */
20
21#if !defined (DWARF2EXPR_H)
22#define DWARF2EXPR_H
23
24/* The expression evaluator works with a dwarf_expr_context, describing
25   its current state and its callbacks.  */
26struct dwarf_expr_context
27{
28  /* The stack of values, allocated with xmalloc.  */
29  CORE_ADDR *stack;
30
31  /* The number of values currently pushed on the stack, and the
32     number of elements allocated to the stack.  */
33  int stack_len, stack_allocated;
34
35  /* An opaque argument provided by the caller, which will be passed
36     to all of the callback functions.  */
37  void *baton;
38
39  /* Return the value of register number REGNUM.  */
40  CORE_ADDR (*read_reg) (void *baton, int regnum);
41
42  /* Read LENGTH bytes at ADDR into BUF.  */
43  void (*read_mem) (void *baton, char *buf, CORE_ADDR addr,
44		    size_t length);
45
46  /* Return the location expression for the frame base attribute, in
47     START and LENGTH.  The result must be live until the current
48     expression evaluation is complete.  */
49  void (*get_frame_base) (void *baton, unsigned char **start,
50			 size_t *length);
51
52  /* Return the thread-local storage address for
53     DW_OP_GNU_push_tls_address.  */
54  CORE_ADDR (*get_tls_address) (void *baton, CORE_ADDR offset);
55
56#if 0
57  /* Not yet implemented.  */
58
59  /* Return the location expression for the dwarf expression
60     subroutine in the die at OFFSET in the current compilation unit.
61     The result must be live until the current expression evaluation
62     is complete.  */
63  unsigned char *(*get_subr) (void *baton, off_t offset, size_t *length);
64
65  /* Return the `object address' for DW_OP_push_object_address.  */
66  CORE_ADDR (*get_object_address) (void *baton);
67#endif
68
69  /* The current depth of dwarf expression recursion, via DW_OP_call*,
70     DW_OP_fbreg, DW_OP_push_object_address, etc., and the maximum
71     depth we'll tolerate before raising an error.  */
72  int recursion_depth, max_recursion_depth;
73
74  /* Non-zero if the result is in a register.  The register number
75     will be on the expression stack.  */
76  int in_reg;
77};
78
79struct dwarf_expr_context *new_dwarf_expr_context (void);
80void free_dwarf_expr_context (struct dwarf_expr_context *ctx);
81
82void dwarf_expr_push (struct dwarf_expr_context *ctx, CORE_ADDR value);
83void dwarf_expr_pop (struct dwarf_expr_context *ctx);
84void dwarf_expr_eval (struct dwarf_expr_context *ctx, unsigned char *addr,
85		      size_t len);
86CORE_ADDR dwarf_expr_fetch (struct dwarf_expr_context *ctx, int n);
87
88
89unsigned char *read_uleb128 (unsigned char *buf, unsigned char *buf_end,
90			     ULONGEST * r);
91unsigned char *read_sleb128 (unsigned char *buf, unsigned char *buf_end,
92			     LONGEST * r);
93CORE_ADDR dwarf2_read_address (unsigned char *buf, unsigned char *buf_end,
94			       int *bytes_read);
95
96#endif
97